Purple bruising on the legs is a relatively common symptom, mainly due to the following reasons: 1, the skin on the legs, especially the skin in front of the tibia is relatively bandit thin, or people with less subcutaneous fat, often unintentional bump, or trauma resulting in subcutaneous bleeding, will produce the symptoms of bruising, especially in young women, the chances of occurrence are relatively high. 2, special types of diseases may also appear purple on the legs, the The symptoms of bruising, especially in the elderly, increased capillary fragility may lead to subcutaneous capillary rupture, bleeding on its own and bruising. 3, the more common blood system diseases, including leukemia and lymphocytic leukemia, thrombocytopenia, can lead to bleeding and bruising on the legs. It is best to go to a regular hospital for a detailed examination to find the real cause of the bruise and for systematic and standardized treatment.